The present invention relates to a processing apparatus and method for performing a process by supplying a processing solution onto a substrate.
In a photoresist processing step of a semiconductor manufacturing process, resist solution is first applied on a surface of a substrate, such as a semiconductor wafer (hereinafter referred to as a wafer), thereby forming a resist film thereon, the resist film on the wafer is exposed with a predetermined pattern and thereafter subjected to development processing by use of a developer solution. Conventionally, a coating/developing system has been used to perform the aforementioned series of processes.
In general, the coating/developing system has a plurality of processing units. The processing units include, for example, an adhesion processing unit for improving the adhesion of resist to the wafer, a resist coating unit for coating the wafer with the resist solution, a thermal processing unit for subjecting the wafer coated with the resist solution to an atmosphere of a predetermined temperature to harden the resist, a thermal processing unit for subjecting the exposed wafer to an atmosphere of a predetermined temperature, and a developer unit for developing the exposed wafer with a developer solution. The wafer is transferred by a transfer mechanism, such as a transfer arm, to be loaded to or unloaded from these processing units, where the respective processes are carried out one after another in the order.
Each of the resist coating unit and the developer unit has a processing chamber called cup in the interior, and the wafer is placed on a rotary table rotatably provided in the processing chamber. In order to carry out the resist coating or developing process, a resist solution or developer solution is supplied onto the wafer from a feeder mechanism such as a nozzle, situated above the wafer, and the wafer is rotated so as to diffuse the resist solution or developer solution on the wafer. During this operation, the resist solution or developer solution may scatter to the periphery, and therefore the processing chamber is surrounded by an appropriate casing. Further, since the exhaust from the resist coating unit or developer unit having the above-described structure contains organic solvent, conventionally, the entire amount of the exhaust is discarded to the central exhaust system of the factory.
However, when the entire amount of the exhaust from the resist coating unit or developer unit is discharged to the central exhaust system of the factory as in the conventional case, the load on the factory exhaust system is increased as the amount of wafers processed is increased, and further the facilities for the operation becomes large in size accordingly. Further, an increase in the number of times of maintenance is inevitable, and naturally the maintenance cost is increased. Furthermore, a separate air supply source for replenishing air by the amount discarded to the central exhaust system of the factory must be provided.